inside is a minilab from environmental sensor start—up aclima that monitors air quality.street view camera platform that has both meteorological instrumentation as well as the inlets. this is where we actually sample the gas, the pollution, as we're driving along. for one year, two street view cars, supped up with aclima tech, criss—crossed west oakland, california — roughly 12 square kilometres — bordered by freeways and home to a bustling port and families. 37,000 kilometres and some serious number crunching later, researchers had this detailed pollution map. steven hamburg, of the environmental defense fund — a partner in the project — explains how. you need fast response instruments that are collecting data every second, and then you need the analytical capability to actually then use that data to actually map it in a way that is just characterising that local spot. each dot represents about 30 metres. the colour indicates air quality. the darker the dot, the dirtier the air. red dots cluster around hotspots, like this metal recycling plant and this busy intersection.